Machine for casting hollow bodies



May24, 193s. f MEEK 2,118,097

MACHINE FOR CASTING HOLLOW BODIES Filed Aug. 19, 1936 ITLWTLZOT- *3 M; 9am SEQ-Am Fer u .Ittorney.

Patented May 24, 1938 iihli'iiZD STATES E ATENT M RGE moment Meek, Milm-ow, England, assigncr to John lioiroyd & Company Limited, Milnrow,

England Appiication August 19, 1936, Serial No. 96,783

2 Claims.

This invention relates to the casting of hollow bodies by means of a mould and parallel core, the core being withdrawn longitudinally from the mould in a progressive manner to prevent its being gripped by the cast metal after it has served its purpose of confining the said metal until it has reached a stage of soli 'ty where it can sustain the form imparted thereto by the mould and core.

To produce castings successfully in the hereinbefore stated manner it is necessary that the core shall lose contact with the partly solidified metal at a moment when solidification is sufficiently advanced to prevent the metal from fiowing, but is not so far advanced as to cause the metal to grip by contraction the core to a degree which will prevent the core from leaving the metal without injury to the surfaces of the core and metal.

It is not possible by present foundry methods to obtain absolute uniformity in temperature of metal at the moment of pouring, temperature of mould and core before and during the casting operation, rate of cooling, and rate of progression of cooling of the metal in the mould over a repeated succession of casting operations. The critical moment in time at which the core must leave the solidifying metal varies with these factors.

A withdrawal of the core by mechanical and automatic methods and means, even if they permit the rate of withdrawal to be varied at will give no indication of the correct rate and moment of withdrawal and the momentarily necessary movement or absence of movement to be thereupon immediately attained and consequently the variations in the said factors are liable to produce sticking of the core and damaged castings or.

leakage of metal when the hitherto know mechanical and automatic methods and means of withdrawal of the core during pouring are en ployed. V

The main object of my invention is to enable uniformly good results to be obtained even when there is a lack of uniformity in the casting conditicns existing during the producing of one casting as compared with those existing during the production of another casting.

To obtain good results the core is usually caused to Withdraw at a slower rate during the first part of the withdrawal movement than at the subsequent part.

I attain this object by the means hereinafter described and illustrated in the accompanying drawing, wherein Figure l is a front elevation, with portions broken away, of a casting machine.

Figure 2 is a side view, with portions broken away of the same machine.

Figure 3 is a plan View in section thereof.

Figure 4 is a detached fragmentary side View of a detail regarded from the opposite side to Figure 2.

To enable my improved machine to be more readily understood I will first indicate with reference to the machine shown in the drawing the casting process to which my invention relates. The said casting process, as performed with the aid of the said machine consists in pouring metal into a removable and preferably quickly rotating mould l and Withdrawing a suspended parallel core 2, whilst the metal is solidifying progressive- 1y from the bottom upwards, the withdrawal of the core 2 taking place progressively in conformity with the solidification so that the core is always operative on the still molten portion of the metal, but is drawn away from the solidifying metal before the same can contract itself onto the core and bind itself to the same to any detrimental extent. r

According to my improved machine the longitudinal withdrawal movement of the core is effected by a gravitational force which is strong enough to pull the core out of the mould against the frictional resistance of the metal therein and to also pull on the hands of an operative, whereby the said gravitational force indicates to the operative, by the strength of its pull on his hands, the frictional resistance of the metal to withdrawal of the core, the operative being enabled, by varying the resistance of his hands to the pull thereon, to vary the strength of the pull on the core, whereby the behaviour of the metal towards the core is indicated to the operative through his hands and the said hands can without delay instantly vary the amount of withdrawal force acting on the core. Thus, this machine enables the core to be withdrawn correctly in spite of lack of uniformity in the rate or time of progressive solidification of the metal, because the said machine has the advantage of gauging and indicating at all times during the casting operation, the condition of the metal in contact with the core.

The said improved machine combines great flexibility in the controlled longitudinal motion of the core with a simple and readily perceived and understood indication to the human sense of feel for the purpose of producing by the hereinbefore specified process uniformly perfect castings notwithstanding lack of uniformity between the temperature, rate of cooling, total time of cooling, manner of solidification and so forth of one pouring of the metal as compared with another.

In the drawing I have illustrated a producing machine which enables the said process to be utilized for mass production in the foundry.

The core 2 is suspended by a universal joint 3 from a. slide 4 which is slidable on parallel pillars 5 and is suspended from one end of a rope 6 which runs on a pulley I loosely mounted on a stationary shaft 8. The other end of the rope 6 is weighted by an adjustable weight 9 provided at each side with a guide groove I9 engaged by the flanges II of stationary parallel guide girders I2 which also serve to support the head I3 which carries the shaft 8. The weight 9 is heavier than the slide 4 and parts suspended therefrom and, therefore operates as a uniform force acting through the rope B to draw the core 2 upwards and thereby withdraw it from the mould I.

The slide 4 is also connected to one end of a rope M which has its other end connected to a winch drum I5 keyed on a shaftIG journalled on the base I I of the machine. The shaft is connected by spur gearing I8, I9 to a shaft 28 which drives a shaft 2| through a pair of toothed bevel wheels 22, 23, a spindle 24 and a pair of bevel wheels 25 and 26. The shaft has a hand wheel 2'1 keyed to it.

A scale 28 of suitable length is fixed to one of the girders I2 and serves, with the aid of an index mark 29 provided on the slide 4, to enable the operative to accurately gauge the momentary position of the lower end of the core 2 and the speed of movement thereof.

In the hereinbefore described machine the ad" justable weight 9 provides the hereinbefore stated gravitational force and the said force operates actively through the rope 6 on the slide 4 and core 2 as the motive power which overcomes the frictional resistance between the metal and the core and raises the core from the shown positioninto a position where the core 2 is completely withdrawn from the mould I. The manual resistance by the operator to this upward movement is exerted 'on the slide 4 through the rope I4 by means of the hand wheel 21, and by the application of more or less force to the hand wheel to resist or overcome the force exerted by the weight 9 the operator can cause the core 2 to move downwards, or'stop or move upwards at any desired speed up to the maximum producible by the weight 9, according to momentary requirements and without great exertion. During this control, the operator continuously re-,

ceives through his hands an indication of the motive power exercised by the weight 9 on his hands in excess of that required to overcome the said frictional resistance.

It will be appreciated that if metal contained in the mould I is completely molten, it will offer no material resistance to the power exerted by the weight 9 to raise the core 2, whereas if the said metal has set and cooled round the core, the consequent frictional resistance will be great enough to completely resist and equalize the pulling power of the weight 9, and that between these two extremes there are conditions of the metal which will produce correspondingly various degrees of resistance to and absorb the pulling power of the weight 9 without preventing the weight 9 from actively withdrawing the core by pulling it up.

'As the weight has a constant motive power and the pull of the weight 9 can be felt by the operators hands holding the hand wheel 21, it follows that when the metal offers no resistance the whole force of the motive power is indicated to the operator through his hands holding the hand wheel, whereas when the metal offers complete resistance the absence of motive power due to the cancellation thereof by the said resistance, will be indicated to the operator through his hands, and that the indication received through the hands will vary between the said maximum and zero and be different for every different amount of resistance of the metal between non-resistance and maximum resistance. The strength of pull felt at each moment by the hands of the operator therefore indicates to him the momentarily existing amount of resistance exercised by the metal.

The operator thus receives exact information at each moment of the casting operation about the strength of the frictional resistance and therefore the state of the metal in contact with the core 2. As the solidification takes place progressively from the bottom upwards,the resistance of the metal to withdrawal of the core 2 is always exercised on the lower end of the rising core 2 and it is the state of the metal momen tarily in contact with the said lower end which is therefore exactly indicated to the operative. Consequently the operative, by the strength of pull on the hand wheel felt by him receives an exact indication of the correct moment when the said lower end should be withdrawn by the motive power of the weight 9 from the solidifying metal in order to prevent the metal from seizing the core after the metal has attained a sufficiently solid state to maintain the form imparted to it by the mould I and core 2.

By permitting rotation of the hand wheel 21 by the said weight at a lesser or greater rate, or

momentarily stopping the said hand wheel, or.

even rotating it in reverse direction the operative can vary and control with great accuracy the position speed and direction of the core 2 instantaneously from moment to moment.

A successful performance of the said casting process is therefore made independent of uniformity in temperature, rate of cooling, behaviour of the metal in cooling, rate of pouring, and so forth, because the hereinbefore described means act as indicators or gauges of the momentary condition of the metal.

To facilitate reintroduction of the core 2 into the mould I, the bearing 32 through which the core extends is arranged so that the core never becomes disengaged therefrom. Furthermore the bearing 32 is provided on a slide 33 which may be counterbalanced by means of ropes 34, pulleys 35 and weights 36, and which loosely supports and centers the upper end of the mould 2. When the mould I is to be removed, the slide 33 is slid upwards on the pillars 5, the bearing 32 sliding along the core 2 which is then in its raised or withdrawn position. On replacing the mould the slide 33 is again slid downwards onto the upper end thereof and the bearing 32 again sliding along the core 2 and maintaining the said core in the correct position to re-enter the mould I when thehand wheel 21 is turned to again lower the core 2 into the mould I.

I claim- 1. A machine for casting hollow bodies of metal comprising a rotary mould, a freely rotatable and axially slidable core for insertion into and withdrawal from the mould, a slide from which the core is suspended, a rope connected to the slide, a bias weight connected to the rope for actuating and thereby Withdrawing the core from the mould, a rope connected to the slide for resisting the withdrawal action of the bias weight and indicating the resistance of the casting to withdrawal ofthe core therefrom, a winch drum for winding on and ofi of the second named rope, and a hand wheel operatively connected to the said winch drum for preventing and checking rotation thereof.

2. A machine for casting hollow bodies of metal comprising a rotary mould, a freely rotatable and axially slidable core for insertion into and withdrawal from the mould, a slide. from which the core is suspended, a rope connected to the slide, a bias Weight connected to the rope for actuating and thereby withdrawing the core from the mould, in combination with manually operated means acting on the bias .weight for resisting the withdrawal action of the bias weight and 10 indicating the resistance of the casting to with drawal of the core therefrom.

CLEMENT MEEK. 

